Leader bar for threading roller machines with strip material



Aug. 13, 1940. J. ca. JONES ET AL LEADER BAR FOR THREADING ROLLERMACHINES WITH STRIP MATERIAL 2 Sheets-Sheet 1 Filed May 9, 1939 JOHN G.JONES ALFRED C ROBERTSON INT0R5 BY 4m ATTORNEYS Aug. 13, 1940. J. c.JONES EI'AL LEADER BAR FOR THREADING ROLLER MACHINES WITH STRIP MATERIAL2 Sheets-Sheet 2 Filed Ma JOHN G. JONES. ALFRED C .ROBERTSON INVENTORSATTORNEYS Patented Aug. 13, 1940 UNITED STATES PATENT OFFHCE LEADER BARFOR THREADING ROLLER MACHINES WITH STRIP MATERIAL Jersey Application May9, 1939, Serial No. 272,660:

20 Claims.

This invention relates to leader bars which may be attached to an end ofstrip material to thread the strip material over rollers. Such machinesare commonly used for cloth tentering,

for drying strip material, for coating and dyeing machines and for otherpurposes where it is desirable to lead strip material through a longpath about a plurality of rollers.

One object of our invention is to provide a leader bar of the type whichis adapted to be carried along by belts with jaws for engaging theconveyor belts. Another object of our invention is to provide a leaderbar with jaw members at each end which are so arranged that the jaws maybe transferred from a clamping position against one belt to a clampingposition against another belt. Another object of our invention is toprovide a leader bar with a means for grasping a belt with apredetermined grip so that an even tension may be exerted by the beltsupon the leader bar as it is passed through the machine. Still anotherobject of our invention is to provide a leader bar with a resilientconnection by which it may be attached to an end of strip material andto enclose this resilient connection inside of the bar. Still anotherobject of our invention is to provide a jaw structure which may have jawmembers for grasping a belt, the jaw members being so arranged that thebelt will be released or will be permitted to slip according to theforces applied to the belt and to the strip material. Other objects willappear from the following specification, the novel features beingparticularly pointed out in the claims at the end thereof.

It has been somewhat diiiicult in the past to successfully thread longstrips of material about machines including a plurality of rollersspaced apart to provide a tortuous path for the material and this isparticularly true where the machines are divided into several sectionswhich may sometimes be used for different purposes. Our inventioncontemplates a leader bar which can be attached to an end of the sheetmaterial and which has at both ends jaws which resiliently graspparallel belts which convey the leader bar through the path about therollers over which the strip material is to be guided. It may bedesirable to move the belt slightly in excess of the speed at which thestrip material is threaded about the rollers, in which case the leaderbar will consequently slip upon its moving belts, or it may be desirableto drive the belts at the threading speed, in which case the slipconnection between the jaws and the belts will only be utilized wheresome undue tension may start to build up on the strip material so thatthe jaws, by slipping on the belts, may prevent the strip material frombeing damaged or torn if it should start to thread improperly.

Coming now to the drawings wherein like reference characters denote likeparts throughout:

Fig. 1 is a longitudinal section with a portion of a leader bar brokenoif showing a leader bar and portions of a jaw construction constructedin accordance with and embodying a preferred form of our invention,parts of this figure being shown in elevation.

Fig. 2 is a fragmentary part section and part elevation showing aportion of the leader bar, the section being taken at right angles tothe section of Fig. l and showing the same leader bar as in Fig. 1.

Fig. 3 is an enlarged fragmentary top plan view showing the jawstructure used at the ends of the leader bar.

Fig. 4 is an enlarged fragmentary section on line 8-4 of Fig. 3, showingthe jaw construction partially in elevation and showing a portion of theleader bar insection.

Fig. 5 is an enlarged sectional view across a fixed and movable jawelement showing the relationship of these two jaws and the cam openinginto which the jaw separator may project.

Fig. 6 is an enlarged fragmentary section showing the resilient grippersurface of the movably mounted jaw and its relationship to the fixedlymounted jaw and belt.

Fig. '7 is a sectional view taken on line l''! of Fig. 2.

Fig. 8 is a fragmentary side elevation showing a portion of the leaderbar, in section, of a machine embodying two belt systems and showing aside elevation of the change-over mechan1sm.

Fig. 9 is an end elevation, partially in section, showing thechange-over mechanism for a belt on one side of a machine, it beingunderstood that similar structures are used on both sidesone for eachbelt.

Fig. 10 is a section on line 10-41) of Fig. 9.

Fig. 11 is a plan view, partially broken away, showing the leader barwith jaws attached to its moving belts, moving an end of stripmaterialior threading a machine, and

Fig. 12 is a perspective view of the end of the slide member.

Referring to Fig. 11, the strip material S may have one end E loopedabout an auxiliary bar I, and this bar, in turn, may be attached bysuitable clips 2 and cables 3 to a leader bar 4 having belt graspingjaws designated broadly as 5 at each end for resiliently grasping a pairof belts 6. Thus, when these belts are moved through any desirable pathfor guiding the strip material S about a plurality of rollers, theleader bar 4 and the auxliary bar I will draw the strip material Sthrough the path defined by the belts 6, thus threading the stripmaterial around the rollers and through the machine.

The particular type of machine embodying a plurality of rollers is notimportant, and since such machines are well known, they will not be morefully described herein.

Referring to Figs. 1 and 2, it will be noted that the strip material S,which is looped about the auxiliary bar I, may be held on the bar bymeans of spring clips 2, or it may be wrapped around the bar, which ispreferably rectangular in shape as shown in Fig. '7, and an end portionE may be sewed, glued or otherwise fastened to the strip material S soas to hold firmly to the auxiliary bar I.

Each of the clips 2 is attached to a cable 3, and the object of thesecables is to exert an even and resilient pull on the strip material whenthe leader bar 4 is moved along by means of the jaws 5 and the belts 6.In order to obtain this resilient and even drag upon the auxiliary barI, the cables 3 are trained over a series of pulleys I mounted entirelywithin the hollow leader bar 5, so that each of the two cables will beattached to an end 8 of a coil spring 9, the other end of which, I0, isanchored upon a shaft II, carried by the leader bar. Thus, the spring 9exerts equal pressure upon both of the cables 3, and any sudden movementof the leader bar 4 will cause the spring 9 to flex and gently transmitthe force to the strip material S.

In order to move the leader bar 4 by means of the belts 6, the leaderbar is provided at each end with a jaw structure broadly indicated at 5.This jaw structure includes a relatively fixed jaw member I2 which isattached to the end I3 of the leader bar and which is provided withelongated openings I4 and with smooth belt-engaging faces I5 on eachside.

Cooperating with this relatively fixed jaw is a pair of movable jawscarried in one piece I6, pivotally mounted at I! upon the ends I3 of theleader bar, which are spaced apart a distance sufficient to permit thejaws I6 to move in between the spaced ends. As indicated in Figs. 3 andl, the pivoted member I6 carries a pair of movably mounted jaws I8,spaced to each side of the pivot I7 and so arranged that either one jawor the other will be resiliently held against the fixed jaw member I2,by means of a spring plunger I9. This spring plunger may be pivotallyattached at 20 to the jaw carrying member l6, and is preferably mountedto slide in a bearing 2! on the oscillatable block 22, this blocklikewise supporting one end of a spring 23 which exerts a thrust uponthe washer 24 to hold the member It in a set position.

As will be obvious from this figure, the spring 23 is efiective to holdeither of the two jaws I8 in an operative position and will increase itsforce upon the member I6 as it passes a dead center across pivot I'I.

Each of the jaw members I8, which are movably mounted with respect tothe jaw I2, carry a spacing lug 25 on the extreme outer ends, thisspacing lug being adapted to engage with a smooth, face I5. of therelatively fixed jaw memher to hold the jaw in a definite relationthereto. Each of the movable jaws is likewise provided with a pair ofspaced lugs 26 which may engage in the apertures I4 and 28 of therelatively fixed jaw member so that they will serve as edge guides tohold the belt 6 in its proper position between one of the movable jawmembers IS and the fixed jaw member I2.

Each of the jaws is so arranged that it will always exert apredetermined and resilient pressure upon the belt member 6. Asindicated in Fig. 6, the movable jaw member I 8 may include a pair ofspaced side walls 29, carrying a shaft 33 arranged diagonally withrespect to the fixed jaw I2 and with respect to a belt 6 lying flat uponthe fixed jaw. On this shaft there is a belt gripping member in the formof a shoe 3I which is normally thrust along the shaft by a spring 32,and by selecting the proper springs, the exact degree of pressure uponthis member can be readily controlled.

With the belt moving in the direction shown by the arrow in Fig. 6, itwill be noted that the spring 32 contacts the shoe 3I with a surface ofthe belt, gripping it between the shoe and the relatively fixed jaw I2.As the belt moves along, if a sudden force should be applied to thebelt, the shoe 3| will tend to move against the pressure of the spring32 so that the belt is permitted to slip. We have found with thisconstruction that the jaws may be permitted to slip all the time, withrespect to the belts, and thread strip material satisfactorily, or theymay be adjusted to grip the belt resiliently and move at the same speedas that of the belt while threading the strip material. In both cases itis desirable to have the resilient shoe on the movable jaw member totake care of-any emergencies which may arise, such as irregularities inthe belt surface, splices or the like, or to permit the jaw members toslip in cases where the machine may be threading improperly for somereason. In any event, a force, above a certain amount, applied to thebelt in excess to the possible speed of travel of the strip materialwill always cause the jaw members to slip.

It is understood that while we have just described a single jaw memberconsisting of the two movable jaws pivotally mounted on one part whichmay be moved relative to one fixedly.

mounted jaw with two belt engaging surfaces, each leader bar has twosets of these jaws, one at each end.

The reason for having this double movable jaw construction is that whereit is desirable to transfer the leader bar from one section of a machineto another, or from one belt to another, this can readily be done, asindicated in Figs. 8, 9 and 10. In these figures, a belt 6 is shownpassing over a pulley 40, this belt having a parallel run indicated atEl relative to a second belt 42 which is trained over the guide pulley43 and which may be driven separately from the belt 6. It is preferable,of course, to have these belts driven at exactly the same speed,although this is not essential. However, it is assumed that the leaderbar is carried by a pair of spaced and parallel belts 6 and that it isdesirable to transfer the leader bar from the belts 6 to the belts 42,this transfer being accomplished rapidly and without permitting anyappreciable quantity of slack to occur between the leader bar and thestrip material. This can be accomplished in the following manner: FromFig. 5, it will be noticed that there is a wedge-shaped edge 43 on oneextreme end of a movable jaw member l8 so that if a sharp member entersbetween the wall 33 and the fiat surface 15 of the relatively fixed jawmember, it may cam the jaw member away from the belt 6 and just as soonas it has cammed the jaw member far enough to cause the pivot 20 to passa dead center with respect to the pivot H, the spring member 23 willexert a thrust upon the jaw member it which is open and cause it torapidly swing to an operative position with respect to the other side ofthe fixed jaw member i2. Thus the parallel run M of the belts 6 may bereleased by one set of movable jaw members just before belts 42 areengaged by the oppo site set of jaw members.

As will be seen from Figs. 8 and 9, a cam member '35 is provided on eachside of the machine, this cam member being arranged in such a positionthat it will pass between the cam surface 43 of a movable jaw member l8and the relatively fixed jaw member. However, it is obvious that just assoon as the leader bar comes to a position in which the jaw members aremoved by the cam members 45 out of a belt-gripping position, the leaderbar can no longer be moved by the belt and must be moved by somesupplemental means.

To accomplish this, we have provided a form of elevator at eachchange-over which operates in the following manner: The elevatingmechanism consists of a hollow slidable bar 45 which is carried by meansof a carriage 41 having rollers 38 freely movable in the grooved rails49.

The carriage carries a fixed rail 41 on which the hollow bar 46 mayslide. As shown in Fig. 12, the hollow bar 6 has the upper wall I46 cutoff short to expose the side walls I41, beveled at the upper edges M8and beveled on the outer edges M9 to facilitate engaging the ends of thestationary jaw members I2. A fiat bottom wall E50 actually performs thelifting operation, each jaw member I2 resting on a wall 1150 in whichthe jaw member is positioned by the side walls I49. This carriage maymove up and down and the slide member 48 may be moved in and out bymeans of the chain 5!! passing over a pair of spaced sprockets 5!. Thechain 50 carries a pin 52 engaging the slide member 46. This chain maybe driven by a known mechanism 56 which is adjusted to drive the chainmembers 50 through one cycle of operations, which, in the presentinstance, is from the position shown in Fig. 9, to the same position,the pin 52 having been driven in one cycle around the lower sprocket 5|,upwardly and over the upper sprocket 5| and back to its initialposition. This movement will cause the slide member 43 to move out underthe jaw members 5 and to engage the jaw members and move them upwardly.Thus the leader bar is engaged and moved by the slide members 46 beforethe jaws release one set of belts, and they are still driven at thepoint where the movable jaw members snap over from one belt-engagingposition to a position to engage the other belt. Since the opposite beltis also moving, just as soon as the movabie jaw member reaches abeltengaging position, the belt carries the leader bar forwardly throughthe machine and the automatic change-over chain has completed its cycleand comes to rest in the position shown in Fig. 9.

The control mechanism is, in the present embodiment, a compressed airsystem, and the air enters a pipe 55, passing through a valve 56 havingaspring valve member 51 which lies in the Path of an operating arm 58,pivoted at 59 upon a suitable bracket 6!! and having an arm member 6|projecting into the path of the jaws of the leader bar. Thus, as theleader bar moves upwardly, being carried along by a belt, it firstengages the lever arm Bi, depressing the valve 57 and permitting air topass through a pipe 63 upwardly into the control box 54, thus releasinga motor to drive the upper sprocket ill a predetermined distance andthen stop. Just as soon as the leader bar pushes the arm 6! upwardly,its

upward movement is assisted by the slide member 46, and this slidemember applies the force necessary to pass the jaws of the leader baracross the cam members it which open the jaws until such a time asspring 23 may close the opposite jaw towards the fixed jaw member forgrasping the opposite belt of the parallel run.

It will be seen from the preceding description that we have provided aleader bar which is resiliently attached to an auxiliary bar which, inturn is attached to the strip material which must be threaded through amachine. Not only is there a resilient connection between the two bars,

but there is likewise a resilient connection between each end of theleader bar and the two belts by which the leader bar is driven. Theforce applied by either pair of movable jaws against either pair offixed jaws can be nicely regulated and is always the same, since inevery case the movable jaws are provided with a resiliently mounted padwhich definitely engages the belt. The remaining portion of each movablejaw is spaced away from the fixed jaw by means of spacing pads, and thebelts are always confined in a definite relationship to the fixed andmovable jaws because of the interengaging belt locating lugs whichcooperate with apertures in the opposite jaw member.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

A leader bar fer threading strip material rollers by of a pair of beltscoman elon ated having fiat extensions at on fixed jaws, a pivotalsupport .l said fiat extensions, an arm having w members mounted on eachpivot, means for hoiding one jaw at each end in a belt engaging positionwith respect to the fixed jaws, and 5 carried by the bar for resilientlyconnect an of the strip material to the bar. 2. A leader bar forthreading strip material about rollersby means of a pair of belts com-'prising an elongated bar having flat extensions at each end formingfixed jaws, a pivotal support near each of said flat extensions, an armhaving two jaw members mounted on each pivot, means for holding one jawat each end in a belt engaging position with respect to the fixed jaws,means carried by the bar for resiliently connecting an end of the stripmaterial to the bar and means carried by each movably mounted jaw forexerting a predetermined pressure on a belt held between the fiatextension and a jaw.

3. A jaw construction for leader bars for grasping a belt comprising abar, a flat extension carried thereby forming a fixed jaw, a pivotcarried adjacent the flat extension, a pair of jaws mounted on the pivotto swing thereon to and from said fixed jaw whereby either jaw may bemoved to a belt grasping position adjacent the fixed jaw on the fiatextension, and a spring for holding one movably mounted jaw against thefixed jaw in a belt grasping position.

4. A jaw construction for leader bars for grasping a belt comprising abar, a flat extension carried thereby forming a fixed jaw, a pivotcarried adjacent the fiat extension, a pair of jaws mounted on the pivotto swing thereon to and from said fixed jaw whereby either jaw may bemoved to a belt grasping position adjacent the fixed jaw on the flatextension, and means carried by each movably mounted jaw for exerting apredetermined pressure upon the belt when said jaw is in a belt graspingposition.

5. A jaw construction for leader bars for grasping a belt comprising abar, a fiat extension carried thereby forming a fixed jaw, a pivotcarried adjacent the fiat extension, a pair of jaws mounted on the pivotto swing thereon to and from said fixed jaw whereby either jaw may bemoved to a belt grasping position adjacent the fixed jaw on the fiatextension, and means carried by each movably mounted jaw for exerting apredetermined pressure upon the belt comprising a shaft angularlydisposed with respect to said jaws, and a gripping shoe slidably mountedon the shaft and spring pressed toward that end of the angularlydisposed shaft lying nearest the belt.

6. A jaw construction for leader bars for grasping a belt comprising abar, a fiat extension carried thereby forming a fixed jaw, a pivotcarried adjacent the fiat extension, a pair of jaws mounted on the pivotto swing thereon to and from said fixed jaw whereby either jaw may bemoved to a belt grasping position adjacent the fixed jaw on the fiatextension, a spring, a mount carried by the bar for one end of thespring and connections between the other end of the spring and thepivoted jaws positioned near the pivot and adapted to hold one movablymounted jaw or the other in belt grasping position when the jaws areswung about through pivotal connection with the bar past a dead centerwith respect to the mount for one end of the spring carried by the bar.

'7. A leader bar for threading strip material about rollers by means ofa pair of belts comprising an elongated bar having flat extensions ateach end forming fixed jaws, a pivotal support near each of said fiatextensions, an arm having two jaw members mounted on each pivot meansfor holding one jaw at each end in a belt engaging position with respectto the fixed jaws, and means carried by the bar for resilientlyconnecting an end of the strip material to the bar including a spring,two cables attached to the spring, pulleys over which the cables passone at one end and the other at the other end of the bar, and means forconnecting the ends of the cables to strip material.

8. A leader bar for threading strip material about rollers by means of apair of belts comprising an elongated bar having fiat extensions at eachend forming fixed jaws, a pivotal support near each or" said flatextensions, an arm having two jaw members mounted on each pivot meansfor holding one jaw at each end in a belt engaging position with respectto the fixed jaws, and means carried by the bar for resilientlyconnecting an end of the strip material to the bar including anauxiliary bar, and resilient means for attaching both ends of theauxiliary bar to the leader bar.

9. A leader bar for threading strip material about rollers by means of apair of belts comprising an elongated bar having fiat extensions at eachend forming fixed jaws, a pivotal support near each of said fiatextensions, an arm having two jaw members mounted on each pivot meansfor holding one jaw at each end in a belt engaging position with respectto the fixed jaws, and means carried by the bar for resilientlyconnecting an end of the strip material to the bar including anauxiliary bar, cables connected to the auxiliary bar, said cablesincluding a resilient connection with the leader bar, and meansincluding the cables and resilient mount for holding the auxiliary andleader bars in parallel relation.

10. A leader bar for threading strip material about rollers by means ofa pair of belts comprising an elongated bar having flat extensions ateach end forming fixed jaws, a pivotal support near each of said flatextensions, an arm having two jaw members mounted on each pivot, meansfor holding one jaw at each end in a belt engaging position with respectto the fixed jaws, and means carried by the bar for resilientlyconnecting an end of the strip material to the bar including anauxiliary bar, cables connected to the auxiliary bar, said cablesincluding a resilient connection with the leader bar, and meanscomprising pulleys over which the cables pass mounted on the leader bar,the cables being directed by the pulleys into a parallel run, and aspring for connecting the parallel cables to the leader bar, wherebyeach cable may give simultaneously when said spring flexes.

11. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate paths in at least portions of which pairs ofbelts have parallel adjacent runs, a leader bar, movably mounted pairsof jaws on each end of the leader bar spaced in accordance with thespacing of the belts, each pair of jaws being adapted to cooperate witha fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and means carried by themachine for swinging the movable jaws upon their pivots, said meansbeing located at a parallel adjacent run of the pairs of belts, wherebysaid jaws may release one of the parallel sets of belts and engage thesecond parallel set of belts thus transferring the leader bar from onemachine section to another.

12. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate paths in at least portions of which pairs ofbelts have parallel adjacent runs, a leader bar, movably mounted pairsof jaws on each end of the leader bar spaced in accordance with thespacing of the belts, each pair of jaws being adapted to cooperate witha fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and means carried by themachine for swinging the movable jaws upon their pivots, said meansbeing located at a parallel adjacent run of the pairs of belts, wherebysaid jaws may release one of the parallel sets of belts and engage thesecond parallel set of belts, and means supplementary to the pairs ofbelts for moving the leader bar while the jaws are swinging about theirpivotal connection with the leader bar.

13. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate 75 paths in at least portions of which pairsof belts have parallel adjacent runs, a leader bar, movably mountedpairs of jaws on each end of the leader bar spaced in accordance withthe spacing of the belts, each pair of jaws being adapted to cooperatewith a fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and means carried by themachine for swinging the movable jaws upon their pivots, said meansbeing located at a parallel adjacent run of the pairs of belts, wherebysaid jaws may release one of the parallel sets of belts and engage thesecond parallel set of belts. and means supplementary to the pairs ofbelts for moving the leader bar while the jaws are swinging about theirpivotal connection with the leader bar comprising a conveyor, meanscarried by the conveyor for engaging and moving the leader bar.

14. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate paths in at least portions of which pairs ofbelts have parallel adjacent runs, a leader bar, movably mounted pairsof jaws on each end of the leader bar spaced in accordance with thespacing of the belts, each pair of jaws being adapted to cooperate witha fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and means carried by themachine for swinging the movable jaws upon their pivots, said meansbeing located at a parallel adjacent run of the pairs of belts, wherebysaid jaws may release one of the parallel sets of belts and engage thesecond parallel set of belts, and means supplementary to the pairs ofbelts for moving the leader bar while the jaws are swinging about theirpivotal connection with the leader bar comprising a conveyor, meanscarried by the conveyor for engaging and moving the leader bar, a sourceof power, a control member for driving the conveyor through the sourceof power, said control member lying in the path of and adapted to beoperated by the leader bar moved by a pair of belts.

15. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate paths in at least portions of which pairs ofbelts have parallel adjacent runs, a leader bar, movably mounted pairsof jaws on each end of the leader bar spaced in accordance with thespacing of the belts, each pair of jaws being adapted to cooperate witha fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and means carried by themachine for swinging the movable jaws upon their pivots, said meansbeing located at a parallel adjacent run of the pairs of belts, wherebysaid jaws may release one of the parallel sets of belts and engage thesecond parallel set of belts, and means supplementary to the pairs ofbelts for moving the leader bar while the jaws are swinging about theirpivotal connection with the leader bar comprising a conveyor, meanscarried by the conveyor for engaging and moving the leader bar,

a source of power connected to the conveyor, a control member for thepower source, means comprising a movable arm for moving the controlmember to drive the conveyor, said movable arm lying in the path of theleader bar moved by a pair of belts, and means for stopping the powerdrive of the conveyor after said conveyor control bar has passed theswinging arm.

16. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate paths in at least portions of which pairs ofbelts have parallel adjacent runs, a leader bar, movably mounted pairsof jaws on each end of the leader bar spaced in accordance with thespacing of the belts, each pair of jaws being adapted to cooperate witha fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and a switch carried by themachine adjacent the parallel pairs of belts, said switch comprisingpairs of cams adapted to engage the movable jaws moving them upon theirpivot to disengage one pair of belts, and spring means acting on saidmovable jaws to engage the movable jaws with another pair of adjacentbelts, and a supplemental means for moving the leader bar while the jawsare engaging the switching cams.

17. In a multiple section machine in which strip material is threadedabout rollers by a leader bar, the combination with a plurality of guidebelts arranged in spaced parallel pairs, of means for guiding the pairsof belts through separate paths in at least portions of which pairs ofbelts have parallel adjacent runs, a leader bar, movably mounted pairsof jaws on each end of the leader bar spaced in accordance with thespacing of the belts, each pair of jaws being adapted to cooperate witha fixed jaw to grasp a belt, a pivot on which the movable jaws aremounted and on which they may turn to bring one movable jaw toward thefixed jaw and into a belt engaging position, and a switch carried by themachine adjacent the parallel pairs of belts, said switch comprisingpairs of cams adapted to engage the movable jaws moving them upon theirpivot to disengage one pair of belts, and spring means acting on saidmovable jaws to engage the movable jaws with another pair of adjacentbelts, and a supplemental means for moving the leader bar, comprising aconveyor, means for moving the conveyor through a cycle through a fixedpath, a source of power for the conveyor, and means for starting theconveyor to move by its source of power including a tripping bar lyingin the path. of the leader bar, said leader bar engaging the trippingbar and starting the conveyor, and means for engaging the leader barcarried by the conveyor whereby the leader bar may be moved past thecams for switching the jaws from one set of parallel belts to another.

18. A leader bar for threading strip material about rollers on a machineby means of parallel belts comprising a tubular member, a fiat extensionproviding a jaw at each end, an arm pivotally mounted near said fixedjaw including two faces constituting a pair of movable jaws, a springadapted to hold one movable jaw or the other against the fixed jaw, aspring mounted inside the tubular member and having one end fastenedthereto, pulleys mounted inside the tubular member including pulleysnear the ends thereof, and two cables attached to the unfastened end ofthe spring, one passing over one end pulley and the other over the otherend pulley and extending from the tubular member, and means forfastening the cables to the strip material.

19. A leader bar for threading strip material about rollers on a machineby means of parallel belts comprising a tubular member, a flat extemsion providing a jaw at each end, an arm pivot ally mounted near saidfixed jaw including two faces constituting a pair of movable jaws, aspring adapted to hold one movable jaw or the other against the fixedjaw, each movable jaw including a belt grasping shoe, a shaft angularlydisposed with respect to the fixed jaw slidably supporting the shoe, anda spring tending to thrust the shoe with a predetermined force against abelt lying against the fixed jaw.

20. A leader bar for threading strip material about rollers on a machineby means of parallel belts comprising a tubular member, a fiat extensionproviding a jaw at each end, an arm pivotally mounted near said fixedjaw including two faces constituting a pair of movable jaws, a springadapted to hold one movable jaw or the other against the fixed jaw, eachmovable jaw including a belt grasping shoe, a shaft angularly disposedwith respect to the fixed jaw slidably supporting the shoe, and a springtending to thrust the shoe with a predetermined force against a beltlying against the fixed jaw, said spring for holding the movable jawagainst the fixed jaw and said shoe spring predetermining the graspingpower of the jaws upon a belt, and smooth surfaces for engaging thebelts upon the jaws whereby the jaws may slip relative to the belts whenthe grasping power of the jaws is insufiicient to overcome the drag of astrip of material being threaded through a machine.

JOHN G. JONES.

ALFRED C. ROBERTSON.

